Existing active diodes used in energy harvester systems often have a comparator in an active rectifier that is powered either by an external power supply or by an energy storage element used to store the harvested energy. The energy storage element can be, for example, a battery or a capacitor. For systems that power the comparator via the energy storage element, the comparator often consumes power from the energy storage element even when the system is not harvesting any energy from the input (energy harvester). By consuming power from the energy storage element when the system is not harvesting energy, the energy storage element can be unnecessarily drained and potentially not sufficiently charged when needed. In order for the comparator to draw power from the energy storage element, the energy storage element needs to have sufficient charge to power the comparator. Accordingly, for systems where the comparator is powered by the energy storage element, the interval between two consecutive charging cycles should not be long enough for the comparator to drain the energy storage element to a point that the energy storage element no longer has sufficient energy to power the comparator, in order for the system to function properly.